Ball point pen cartridge



Nov. 19, 1957 F. H. SEYER BALL POINT PEN CARTRIDGE Filed A ril 12. 1954 IN V EN TOR.

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. per base alloy like a suitable brass.

limited States Patent BALL POINT PEN CARTRIDGE Frank H. Sayer, Los Angeles, Calif., assignor, by mesne assignments, to Paper Mate Manufacturing Company, ,Culver City, Calif., a corporation of Delaware Application April 12, 1954, Serial No. 422,305

Claims. (Cl. 1 --42.4)

The present invention relates to fountain pens, and more particularly to the ink container portions of such pens.

In ball point pens, a supply or reservoir of ink is contained within a tubularmember or cartridge having a ball at its forward end which functions as the writing tip. The ink flows onto the ball in the cartridge, being conveyed to the writing paper, or other writing surface, as the ball rolls in the cartridge as a result of moving it over the writing surface. The rearward end of the cartridge is open to atmosphere which allows the ink level in the cartridge to drop as the ink is consumed, insuring a steady supply of ink to the ball, until the cartridge is empty.

As a rule, the balls of the writing instruments are made of steel, while the tubular member containing the ink supply may be made of a dissimilar metal, such as a cop- After the passage of substantial time (for example, six to twelve months), a film or crystal growth has sometimes been noted at the rearward, open end of the tubular member. This film or growth acts as a plug tending to close the rearward end of the tubular member, preventing the ink supply from being acted on by atmospheric pressure for the purpose of assuring the feeding or free flowing of the ink onto the ball. The film or crystal growth is apparently caused by the oxidizing of the ink at the rearward end of the ink tube, probably due to a reaction between the ink and the brass tube in the presence of air or oxygen. The forma tion of the film or crystal growth may also be enhanced by electrolytic corrosion effects occasioned by the dissimilar steel ball and copper base or brass tube in the presence of the ink.

Accordingly, it is an object of the present invention to prevent or minimize the formation of plug-like masses on the ink at the rearward end of the ball point ink tubes made of metal, in order in insure appropriate supply of ink to the balls as the ink is consumed.

Another object of the invention is to prevent deleterious reaction between a metallic ball point ink tube and the ink contained therein.

useful life of a ball point pen cartridge by preventing deterioration of the ink supply with the passage of time. invention possesses many other advantages, and has other objects which mav be made more clearly apparent fro a consideration f a form in which it may be embodied. This form wt: in the drawings accompanying and forming the present specification. it will now be descrluecl. in detail, for the purpose .iples of the invention; but it is to be understood a t such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

2,813,513 Patented ov. '19, 1957 Referring to the drawings:

Figure 1 is a side elevational view, partly in section, 1

of an ink cartridge for a ball point pen embodying the invention;

Fig. 2 is an enlarged longitudinal section of a portion of the ink tube or reservoir;

Fig. 3 is an enlarged longitudinal section through the writing tip of the ball point pen. 1

As disclosed in the drawings, a ball point cartridge 10 is provided, which forms an essential portion of a ball point writing instrument. The cartridge includes ;an elongate ink tube or container 11 havingan open rearward or upper end 12. The forward portion 13 of the tubular member 11 is suitably secured in leakproof fashion over the rearward portion 14 of the ball point writing tip 15. This tip includes a generally tubular body 16 having an ink passage 17 communicating with the interior of the ink container or tube 11. Atthe forward end of the body 16 is provided a socket 18 in which the writing ball 19 is contained. This ball is retained in the socket by deforming the generally frusto-conical nose 20 of the tip around an equatorial zone of the ball. The

nose 2d is not clamped around the ball 19, but has an appropriate clearance therewithallowing the passage of ink between the ball and the nose, while preventing such ink from flowing around the ball in the absence of rotation of the ball 19 in the socket 18.

A suitable seat 21, which is preferably curved to conform to the curvature of the ball, is provided adjacent the rear portion of the latter, againstwhich the ball will bear while being pressed upon a writing surface. This seat 21 has a plurality'of circumferentially spaced, longitudinally extending channels or flutes 22 therein, which will allow the ink to flow from the ink passage 17 and onto the external surface of the ball 19, i

The ink tube 11 and body 16 of the writing tip 15 contain ink 23 of the appropriate and desired type, the upper or rearward end 12 of the tube being open to atmosphere. Thus, as the ball 19 is rolled over writing paper, or other writing surface, and the ink is consumed, the presence of the atmospheric pressure-atthe rearward end of the tube will insure the downward movement of the ink 23 in the cartridge and its steady supply onto the surface of the ball 19. f

in one form of cartridge, it is usual practice to make the ink tube 11 of brass, or equivalentlcopper base 'alloy. It is also usualprac'tice to make the tip 15 that fits into the forward end 13 of the tube ,11 of brass, or an equivalent copper base alloy. The ball 19 itself is ,made of a suitable steel. As noted above, a film or crystal growth sometimes has formed atthe rearward end 12 of the ink supply 23, plugging such end and preventing atmospheric pressure from being effective to shift the reservoir of ink toward the ball as the ink is consumed. As a result, the ink 23 will not flow freely onto the ball, resulting in improper operation of the writing instrument.

The film or crystal growth may be caused by the oxidizing of the ink 23 in view of its contact with air. It is also believed to be due to a relatively slow chemical reaction between the ink andthe brass ink tube 11. Moreover, the presence of the film or crystalgrowth is also thought to be due to the fact that the ink tube 11 is made of a metal which is dissimilar to the steel ball 19. The steel ball and the brass tube in the presence of and in contact with the ink 23, which acts as an electrolyte,

. appear to provide an electrolytic corrosive action at the 'that' occurs'between the b i a ss of the tube 11 and the "ink 23 in the presence of oxygen in the air.

viithth 1111:23 9: 1

I It has been found that by coating the inner surface of 'th'iiiktube' lf'with silver1'24, the above harmful effects are considerably minimized, if not completely eliminated.

If desired, a silver coating 26 may also be provided on the exterior of the ink tube or container 11.

The silver coating or plating 24 and 26 may be secured by electrolytically depositing silver upon the inner surfaces-of the inktubell, as well as upon its outer surface, if'an external coating 26 is also'desired. However, the silver 'coating may:alsobeapplied by other means, as by dippingthe:partsin a"silver-solution.

In place of employing silver coatings, coatings of i nickel, or'chromi um can be used. 1 Such coating materials have been found to accomplish the objectives of the invention, although it is preferred to plate the inner surfaces ofv the tube 11 and pen tip 15 with silver, as specifi- :cally described above;

:rWith'the" coated tubell, it has been found that the formation of the film or crystal growth at the upper or rearward end of the inksupply 23 is prevented, even after cartridges containing the ink have been stored for com siderableperiodsfof time. .The silver plating 24 eliminates the reaction between the brass tube 11 and the ink 23, and also prevents-electrolytic corrosion effects due to the dissimilar metals from. which the ball 19 and ink tube 11, as well as the writing tip 15, are made.

' The inventor claims 1. In ball point writing instruments: a metallic tubular ink container having a rearward portion exposed to the atmosphere; a tubular tip secured to the forward portion of said container in'fluid communication therewith; ink

in said container and tip; a metallic ball of a dissimilar metal from said container confined within the forward portion of saidtip and projecting therefrom; and a metallic material coating the inner wall of said container which is non-reactive with said ink in the presence of said ball, said metallic material having substantially the same potential as said balL 2. In ball point writing'instruments: a copper base alloy tubular ink container having a rearward portion exposed to the atmosphere; a tubular tip secured to the forwa-rd portion o f.sa id :container in fluid communica- 3 tion therewith;,ink; in said container and tip; a steel ball I wco nfined within the for ward portion of said tip and projecting therefrom; and a metallic material coating the inner wall of said container which is non-reactive with said ink inthe presence of said ball, said metallic material having substantially. the same potential as said ball.

Y 3.; In ballpoint writing instruments: a brass tubular ink container having a rearward portion exposed to the atmosphere; a tubular; tip secured to the forward portion of said container in fluid communication therewith; ink

in said container and-tip; a steel ball confined within the forward portion. of said tip and projecting therefrom; and

- a metallic material coating the inner wall of said cont ainer which is non-reactive with said ink in the presence of said ball said. metallic material having substantially the same potential asfsaidball.

4. In ball point writing instruments: a metallic tubular ink container having a rearward portion exposed to the atmosphere; a tubular tip secured to the forward portion of said container in fluid communication therewith; ink in said container and tip; a ball of a dissimilar metal from said container confined within the forward portion of said tip and projecting therefrom; and a silver coating on the inner wall of saidcontainer extending from its rearward portion to said tip; said ball having substantially the same potential as said silver coating.

5. In ball point writing instruments: a metallic tubular ink container. having a rearward portion exposed. to, the atmosphere; a tubu lar tip secured to the forward portion of said container in fluid communication therewith; ink in said container and tip; a ball of. a dissimilar metal from said container confined within the forward portion of said tip and projecting therefrom; and a silver coating on the inner and outer walls of said container extending from the rearward portion of said container to said tip;

said ball having substantially the same potential as said silver coating.

"6. In ballpointxwriting instruments: a copper base fined within the forward portion of said tip and projecting therefrom; and a silver coating on the inner wall of said container extending from said rearward portion to said tip.

j .7. Iri ballpoint writing instruments: a brass tubular ink container having a'rearward portion exposed to the atmosphere; a tubular tip secured to the forward portion of said container in fluid communication therewith; ink in said container and tip; a steel ball confined within the forward portion of said tip and projecting therefrom; and a silver coating on the inner wall of said container extending from said rearward portion to said tip.

8. In ball point writing instruments: a brass tubular ink container having a rearward portion exposed to the atmosphere; a tubular tip secured to the forward portion of -saidcontainer in' fluid communication therewith; ink in said containerand tip; a steel ball confined within the tit) forward portion of, said tip and projecting therefrom; and a silver coating on the inner and outer walls of said container extending from said rearward portion to said In; a ball pointed writing instrument as stated in lclaimll, whereinthe metallic material coating is nickel.

i 1 References Cited in the file of this patent Great Britain May 17, 1950 

